A health worker wearing Ebola protection gear leaves a changing room before entering the Biosecure Emergency Care Unit at an Ebola treatment centre in Beni, in the Democratic Republic of Congo, March 30, 2019. [Reuters]

A five-year-old boy has died of Ebola in Uganda, a health official said on Wednesday, in the first case of the disease crossing the border from the current outbreak in the Democratic Republic of Congo.

The boy died overnight, the official told Reuters, after entering Uganda from Congo with his family. His mother had returned to Congo to nurse her father, who died of the disease, the health minister said on Tuesday.

The official asked not to be named.

Four of the boy's relatives are being monitored in isolation wards and two of them are being tested for Ebola after exhibiting symptoms of the disease, the health minister said on Tuesday. Results are expected on Wednesday.

The boy's case is the first known example of Ebola crossing the border since the current outbreak began in August in the neighbouring Democratic Republic of Congo.

Experts from Uganda's health ministry, the World Health Organization (WHO) and the US Centres for Disease Control and Prevention (CDC) have been dispatched to the area of the outbreak.

Congo's health ministry said on Monday that it had recorded 2,062 cases of Ebola, including 1,390 deaths, since the epidemic began in eastern Congo.